Tim Wescott wrote:

W. Watson wrote:

I bought this antenna on a 30 day trial, and just got it about 12
hours ago. So far I'm not at all impressed. I live about 150 miles
.... snip

during that period. In fact, quite listenable. All this without the
device though.

I'll continue to experiment, but so far not so good. Comments?


I'd change the power supply to a better brand.

Generally if you have atmospheric or man-made noise increasing the
antenna efficiency is just going to increase the noise along with the
signal.

You could try to make a directional antenna; this would increase your
desired signal more than your noise.

The antenna would have to be big, however. The wavelength at 800kHz is
somewhere around 370 meters and you'd need to use around 1/4 of this.

You could try to feed power supply noise to the radio antenna at just
the right amplitude and phase to null it out. This would be a good
subject for an undergraduate or even a Master's thesis in EE but
probably not a good thing to do in practice.

You could attempt to shield it. Rat Shack has some clamp-on ferrites,
you could put one of these on your power cord close to the end that
plugs into the power supply. You could also make sure that the PC case
is well shielded.

I tried the RS ferrites and they made no change. I even took barbell weights
and put them on the AC line of the PC. Zippo. If I hadn't already spent $60
for the new PSU six weeks ago, I might think of buying a much better one.

In some way this may be circuit dependent. I do believe I plugged in my
other PC to the same socket and had the same experience; however, when it's
plugged into its normal socket, there is no noticeable change.

Interestingly, bad weather moved in yesterday and today, and reception from
the station has been quite good with the normal antenna. This stuff can get
pretty strange.

--
Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
(121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet

Traveling in remote places in the winter. What's the best
tool to carry with you? An axe.
-- Survivorman, Discovery (SCI) Channel

Web Page: home.earthlink.net/~mtnviews

Allodoxaphobia wrote:

On Tue, 29 Nov 2005 11:36:09 GMT, W. Watson wrote:

I bought this antenna on a 30 day trial, and just got it about 12 hours ago.
So far I'm not at all impressed. I live about 150 miles from an AM station,
at 810, in the SF/SJ Bay Area, which has a marginal signal, but usually
listenable. Putting a new PSU in a PC about a month ago increased the noise
in AM radios 70-100' from the PC to an almost unacceptable level. I had
hoped the antenna would boost the signal enough to knock down the noise.


The 'noise' is _also_ a signal -- just one that nobody wants to receive.
The "C. Crane's Twin Ferrite Antenna" happily 'improves' the reception
of the noise -- in addition to the signal(s) you desire.

Let me guess: That PSU was "Made in China".

Jonesy
Yes, you absolutely guessed the right country. I called the tech support and
they were less than useful. I asked about a circuit diagram. Sorry, we don't
have one to give out.

The trick here is that I see absolutely no change at all. One would think
maybe the volume might increase, but nay.

--
Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
(121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet

Traveling in remote places in the winter. What's the best
tool to carry with you? An axe.
-- Survivorman, Discovery (SCI) Channel

Web Page: home.earthlink.net/~mtnviews

Michael Coslo wrote:

W. Watson wrote:

I bought this antenna on a 30 day trial, and just got it about 12
hours ago. So far I'm not at all impressed. I live about 150 miles
from an AM station, at 810, in the SF/SJ Bay Area, which has a
marginal signal, but usually listenable. Putting a new PSU in a PC
about a month ago increased the noise in AM radios 70-100' from the PC
to an almost unacceptable level. I had hoped the antenna would boost
the signal enough to knock down the noise. There are times when I can
get a good signal from the station, but certainly less frequently than
before.


Any rf noise put out by the computer ps is going to be picked up by
your antenna as well as the radio station you are trying to hear. So a
better antenna (if your new one is indeed better) wil just pick up
stronger power supply noise. It's moslty a null situation.

What you need to do is get that power supply fixed or replaced

- 73 de Mike KB3EIA -

I think the only solutions to the PSU problem is to buy a much better one.
As I mention above, that's probably a losing proposition. I doubt after 6
weeks they would take it back. It might be worth a try though. Note my
comment above to someone a few moments ago that this seems to be a household
circuit dependent problem. Another PC in the same room works fine until I
plug it into the socket that I first noticed the problem.



--
Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
(121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet

Traveling in remote places in the winter. What's the best
tool to carry with you? An axe.
-- Survivorman, Discovery (SCI) Channel

Web Page: home.earthlink.net/~mtnviews

Phil Wheeler wrote:

W. Watson wrote:


I'll continue to experiment, but so far not so good. Comments?


As others have said, you should try to attenuate the noise at its
source. If it is radiated, you need a better PSU. If it is coming out
on the PCs AC line, line filters might help.

If the PC and KGO are not in the same direction, some sort of
directional antenna might help.

Of course, the ultimate solution would be to move to SF and get a really
big signal. But there are problems with that, too: I live abt 3-4 miles
west of KNX (50 KW, 1070 KHz) and my problem is avoiding it, not making
it stonger

Phil
Yes, I've had that experience with close stations. You can probably listen
to it through the bed springs. :-)

Attempts to shield the AC with the RS ferrite block and a barbell weight
failed. See comment about household circuit dependency in my just posted
responses above yours.

--
Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
(121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet

Traveling in remote places in the winter. What's the best
tool to carry with you? An axe.
-- Survivorman, Discovery (SCI) Channel

Web Page: home.earthlink.net/~mtnviews

W. Watson wrote:

In some way this may be circuit dependent. I do believe I plugged in my
other PC to the same socket and had the same experience; however, when
it's plugged into its normal socket, there is no noticeable change.


Grounding issue?

W. Watson wrote:
Phil Wheeler wrote:

W. Watson wrote:


I'll continue to experiment, but so far not so good. Comments?



As others have said, you should try to attenuate the noise at its
source. If it is radiated, you need a better PSU. If it is coming
out on the PCs AC line, line filters might help.

If the PC and KGO are not in the same direction, some sort of
directional antenna might help.

Of course, the ultimate solution would be to move to SF and get a
really big signal. But there are problems with that, too: I live abt
3-4 miles west of KNX (50 KW, 1070 KHz) and my problem is avoiding it,
not making it stonger

Phil

Yes, I've had that experience with close stations. You can probably
listen to it through the bed springs. :-)


I hope not: Still use a water bed

Attempts to shield the AC with the RS ferrite block and a barbell weight
failed. See comment about household circuit dependency in my just posted
responses above yours.


Got it!

On Wed, 30 Nov 2005 02:54:34 GMT, "W. Watson"
wrote:

Interestingly, bad weather moved in yesterday and today, and reception from
the station has been quite good with the normal antenna. This stuff can get
pretty strange.

Classic indication of a bad ground, or a ground loop.

73's
Richard Clark, KB7QHC

In article t,
W. Watson wrote:

I tried the RS ferrites and they made no change. I even took barbell weights
and put them on the AC line of the PC. Zippo. If I hadn't already spent $60
for the new PSU six weeks ago, I might think of buying a much better one.

Ferrites clamped around the power cable will help with common-mode RF
noise. They won't do anything to help cancel out differential-mode
noise.

It'd probably be beneficial for you to try to get a robust powerline
noise filter. These will filter out both common-mode noise, and
differential noise as well.

Unfortunately, it's possible that the new power supply is radiating RF
directly, rather than feeding it back into the mains. If so, nothing
other than replacing it, or switching to a PC case with better
shielding, is likely to help the problem.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Richard Clark wrote:

On Wed, 30 Nov 2005 02:54:34 GMT, "W. Watson"
wrote:


Interestingly, bad weather moved in yesterday and today, and reception from
the station has been quite good with the normal antenna. This stuff can get
pretty strange.


Classic indication of a bad ground, or a ground loop.

73's
Richard Clark, KB7QHC
If so, how do I track it down?

--
Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
(121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet

Traveling in remote places in the winter. What's the best
tool to carry with you? An axe.
-- Survivorman, Discovery (SCI) Channel

Web Page: home.earthlink.net/~mtnviews

W. Watson wrote:
Michael Coslo wrote:

W. Watson wrote:

I bought this antenna on a 30 day trial, and just got it about 12
hours ago. So far I'm not at all impressed. I live about 150 miles
from an AM station, at 810, in the SF/SJ Bay Area, which has a
marginal signal, but usually listenable. Putting a new PSU in a PC
about a month ago increased the noise in AM radios 70-100' from the
PC to an almost unacceptable level. I had hoped the antenna would
boost the signal enough to knock down the noise. There are times when
I can get a good signal from the station, but certainly less
frequently than before.



Any rf noise put out by the computer ps is going to be picked up
by your antenna as well as the radio station you are trying to hear.
So a better antenna (if your new one is indeed better) wil just pick
up stronger power supply noise. It's moslty a null situation.

What you need to do is get that power supply fixed or replaced

- 73 de Mike KB3EIA -

I think the only solutions to the PSU problem is to buy a much better
one. As I mention above, that's probably a losing proposition. I doubt
after 6 weeks they would take it back. It might be worth a try though.
Note my comment above to someone a few moments ago that this seems to be
a household circuit dependent problem. Another PC in the same room works
fine until I plug it into the socket that I first noticed the problem.


Hmmm, just maybe, you might be able to ditch it as a warranty item.
Dunno tho' as it will depend on the outfit that sold it to you. I don't
know if you are a Ham or not, but if you are, you might play the part 15
card, as they are required to not interfere. I suspect that a 160 meter
rig might catch the same interference.

It is kind of a drag though, since IIRC a noisy switcher Power supply
is hard to fix. Good luck!

- 73 de Mike KB3EIA -